Recently, there has been considerable interest within the detergent industry for laundry detergents which have the convenience, aesthetics and solubility of liquid laundry detergent products, but retain the cleaning performance and cost of granular detergent products. The problems, however, associated with past granular detergent compositions with regard to aesthetics, solubility, flowability after standard storage conditions and user convenience are formidable. Such problems have been exacerbated by the advent of “compact” or low dosage granular detergent products which typically do not dissolve in washing solutions as well as their liquid laundry detergent counterparts. These low dosage detergents are currently in high demand as they consume resources and can be sold in small packages which are more convenient for consumers prior to use, but less convenient upon dispensing into the washing machine as compared to liquid laundry detergent which can be simply poured directly from the bottle as opposed to “scooped” from the box and then dispensed into the washing solution.
As mentioned, such low dosage or “cornpact” detergent products unfortunately experience dissolution problems, especially in cold temperature laundering solutions (i.e., less than about 30° C.). More specifically, poor dissolution results in the formation of “clumps” which appear as solid white masses remaining in the washing machine or on the laundered clothes after conventional washing cycles. These “clumps” are especially prevalent under cold temperature washing conditions and/or when the order of addition to the washing machine is laundry detergent first, clothes second and water last (commonly known as the “Reverse Order Of Addition” or “ROOA”). Such undesirable “clumps” are also formed if the consumer loads the washing machine in the order of clothes, detergent and then water. Similarly, this clumping phenomenon can contribute to the incomplete dispensing of detergent in washing machines equipped with dispenser drawers or in other dispensing devices, such as a granulette. In this case the undesired result is undissolved detergent residue in the dispensing device.
It has been found that the at least a portion of the dissolution profile of a granular detergent composition is impacted by the process used to manufacture that detergent. For instance, the dissolution profile of a detergent composition may be impacted by the uniformity of the particles in the composition with respect to both density and size of the particles. This uniformity in turn is dictated in large part by the process by which the detergent is manufactured. However, to date manufacturing processes have been largely unsatisfactory in delivering compositions of the desired uniformity.
Accordingly, the need remains for a process for the manufacture of detergent compositions which can provide compositions of the desired uniformity and as such exhibits improved solubility, is more aesthetically pleasing to consumers, has improved flowability and exhibits improved cleaning performance.